Once you've chosen which type of annotation you want to insert, use the settings underneath the "Add annotation" button to change the font size, color, or background color.

Position the annotation on the video by dragging and dropping it within the video player. Use the small black squares on the corners of the annotation to make them bigger or smaller. Annotations have a size limit and they are only allowed to cover up to 30% of the player size. You won't be able to increase the size of the annotations after that point.

Check the "Link" box underneath the "Start" and "End" settings. You can choose whether you want the annotation to link to another video, your channel, a playlist, a fundraising site or direct the users to subscribe to your channel.